Sentinel Transaction Safety

Pre-execution transaction safety oracle for autonomous AI agents. Before signing an on-chain transaction, an agent calls SENTINEL and receives a SAFE / UNSAFE / UNKNOWN verdict, a standardized SENTINEL Score (0-100, grade AAA-D), and an ed25519-signed receipt. Checks contract security (GoPlus), execution simulation (Alchemy eth_call), honeypot detection (honeypot.is), and LP concentration/rug risk. Pay-per-call via x402 ($0.005 USDC on Base) — no accounts, no API keys, no SDK required. No free trial.

⚠️ Data Handling Notice: SENTINEL sends the unsigned transaction payload (chain, sender, tx data) to a remote API (sentinel-agent.dev) for evaluation. The payload is processed to produce a verdict and is not required to be a signed or broadcastable transaction. Review the transparency notice below before sending any transaction containing sensitive calldata.

SENTINEL — Agent Transaction Safety Oracle v1.0.0

A pre-execution safety oracle for autonomous AI agents. Before an agent signs a blockchain transaction, it calls SENTINEL and gets back a SAFE / UNSAFE / UNKNOWN verdict, a standardized SENTINEL Score (0–100, grade AAA–D), and a signed receipt — all before a single unit of value moves. Pure M2M, pay-per-call via x402, no accounts.

Running on FastAPI + Supabase + Render — the same production stack as the rest of this M2M model family (VeraData, Intelica, TrustBoost).

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⚠️ Transparency Notice (Read Before Installing)

1. Data Transmission

The transaction payload you send (chain, from, tx) is transmitted to Render (AWS) infrastructure for processing via FastAPI.

What SENTINEL evaluates: contract security (GoPlus), execution simulation (Alchemy eth_call), honeypot cross-check (honeypot.is), and LP concentration. The evaluation is produced by rule-based checks plus an LLM council (Claude Haiku + GPT-4o-mini) server-side.

What SENTINEL stores: verdict, payer address, chain, and price paid, logged to Supabase for usage tracking. It does not require or store your wallet's private key at any point.

For strict no-transmission requirements (air-gapped systems, or transactions containing sensitive calldata that must never leave the local machine): this service is not suitable.

2. Payment Model and Autonomous Safety

SENTINEL uses x402 with local EIP-3009 verification — no facilitator dependency for verification, no human confirmation needed.

How autonomous payment works safely:

1. Agent calls POST /v1/guard without payment → receives HTTP 402 with accepts (network base, price $0.005 USDC, payTo published in the response).
2. Agent signs an EIP-3009 TransferWithAuthorization for the exact amount, using its own wallet's private key — that signature never leaves the agent's own environment.
3. Agent retries the request with the signed authorization in the X-PAYMENT header.
4. SENTINEL recovers the signer locally (eth_account.recover_message) and verifies it against the expected wallet — no third-party facilitator call required to validate the payment.
5. Verdict + signed receipt are returned only after verification succeeds.

Why this is safe for autonomous agents:

• The agent's private key never touches SENTINEL infrastructure — only the resulting signed authorization does.
• Verification is local and deterministic (cryptographic signature recovery), not an opaque third-party call.
• SENTINEL cannot initiate a charge — the agent must construct and sign the authorization itself.

No trial mode. Unlike other services in this model family, SENTINEL has no free preview endpoint today. Every call to /v1/guard requires a valid payment; there is no tx_hash=TRIAL equivalent. Budget for $0.005 USDC per pre-execution check.

3. Audit Trail

Every call is logged to Supabase (sentinel_usage) with: verdict, payer address, chain, and price — never the full calldata beyond what was needed for evaluation.

4. Operator Verification

• GitHub: https://github.com/teodorofodocrispin-cmyk
• Repository: https://github.com/teodorofodocrispin-cmyk/sentinel-public
• Health endpoint: https://sentinel-agent.dev/health
• Pricing: https://sentinel-agent.dev/pricing

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When to use this skill

Activate this skill when:

• An agent is about to sign an on-chain transaction on Base and wants a pre-flight safety check (rug pull, honeypot, malicious contract, infinite approval).
• The agent needs a signed, independently verifiable SAFE/UNSAFE/UNKNOWN verdict before spending funds.
• The agent's wallet has budget for per-call payment ($0.005 USDC) — there is no free fallback.

When NOT to use this skill

• Strict zero-transmission environments (air-gapped, on-premise) — the transaction payload leaves the local machine.
• Any agent without an x402-capable wallet able to sign EIP-3009 authorizations on Base. There is no no-wallet preview to fall back to.
• Transactions containing calldata that must never be transmitted to a third party.

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How it works

1. Agent POSTs {chain, from, tx} to sentinel-agent.dev/v1/guard.
2. SENTINEL runs contract security (GoPlus), simulation (Alchemy eth_call), honeypot cross-check (honeypot.is), and LP concentration analysis.
3. An LLM council (Claude Haiku + GPT-4o-mini) reviews the aggregated signals.
4. SENTINEL returns a JSON verdict (SAFE / UNSAFE / UNKNOWN), a 0–100 risk score with AAA–D grade, the contributing risk signals, and an ed25519-signed receipt.

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Try it — check pricing and health first (free, no wallet needed)

bash

curl https://sentinel-agent.dev/health
curl https://sentinel-agent.dev/pricing

These two endpoints are free and require no payment. POST /v1/guard itself always requires payment — there is no free equivalent.

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API Request

Endpoint: POST https://sentinel-agent.dev/v1/guard Headers: Content-Type: application/json, X-PAYMENT: <x402 signed authorization>

json

{
  "chain": "base",
  "from": "0xYourAgentWallet",
  "tx": { "to": "0xTargetContract", "data": "0x...", "value": "0x0" }
}

API Response (no payment, 402)

json

{
  "x402Version": 2,
  "accepts": [
    { "network": "base", "amount": "5000", "payTo": "0xCf1d31020A7915421f6d66B9835Dcb6f422337E7" }
  ]
}

API Response (success, 200)

json

{
  "verdict": "SAFE",
  "sentinelScore": 94,
  "grade": "AAA",
  "contract": { "risks": [] },
  "lpConcentration": "locked",
  "signature": "ed25519:...",
  "signer": "sentinel-agent.dev"
}

SENTINEL Score grading

Grade	Score range	Meaning
AAA	90-100	No material risk signals detected
AA/A	70-89	Minor advisory signals, no hard risks
BBB/BB/B	40-69	Moderate risk signals present
CCC/CC/C	15-39	Significant risk signals
D	0-14	Hard risk detected (honeypot, extreme LP concentration, simulation failure)

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Known Limitations

• No free trial or no-wallet preview endpoint exists today. Every /v1/guard call requires payment.
• Verdicts reflect the checks currently implemented (GoPlus contract security, Alchemy simulation, honeypot.is, LP concentration); they are not a guarantee against novel or unseen attack patterns.
• KNOWN_LOCKERS (used for LP-lock detection) currently covers UNCX on Base; liquidity locked in unlisted lockers may be scored as moderate (advisory) instead of locked (clean).
• No certified audit: the SENTINEL Score is produced by rule-based checks plus an LLM council, not by a certified security firm.
• Paid endpoint verification is local/facilitator-free for /verify; on-chain settlement of the payment itself still depends on a settler submitting the authorization (self-settle or facilitator).

Resources

• GitHub: https://github.com/teodorofodocrispin-cmyk/sentinel-public
• Health check: https://sentinel-agent.dev/health
• Pricing: https://sentinel-agent.dev/pricing
• Agent card (A2A): https://sentinel-agent.dev/.well-known/agent.json
• Docs (LLM-readable): https://sentinel-agent.dev/llms.txt
• MCP server: https://sentinel-agent.dev/mcp
• Infrastructure: FastAPI + Supabase + Render (AWS)